"""
Rados benchmarking sweep
"""
import contextlib
import logging
import re

from io import BytesIO
from itertools import product

from teuthology.orchestra import run
from teuthology import misc as teuthology

import six

log = logging.getLogger(__name__)


@contextlib.contextmanager
def task(ctx, config):
    """
    Execute a radosbench parameter sweep

    Puts radosbench in a loop, taking values from the given config at each
    iteration. If given, the min and max values below create a range, e.g.
    min_replicas=1 and max_replicas=3 implies executing with 1-3 replicas.

    Parameters:

        clients: [client list]
        time: seconds to run (default=120)
        sizes: [list of object sizes] (default=[4M])
        mode: <write|read|seq> (default=write)
        repetitions: execute the same configuration multiple times (default=1)
        min_num_replicas: minimum number of replicas to use (default = 3)
        max_num_replicas: maximum number of replicas to use (default = 3)
        min_num_osds: the minimum number of OSDs in a pool (default=all)
        max_num_osds: the maximum number of OSDs in a pool (default=all)
        file: name of CSV-formatted output file (default='radosbench.csv')
        columns: columns to include (default=all)
          - rep: execution number (takes values from 'repetitions')
          - num_osd: number of osds for pool
          - num_replica: number of replicas
          - avg_throughput: throughput
          - avg_latency: latency
          - stdev_throughput:
          - stdev_latency:

    Example:
    - radsobenchsweep:
        columns: [rep, num_osd, num_replica, avg_throughput, stdev_throughput]
    """
    log.info('Beginning radosbenchsweep...')
    assert isinstance(config, dict), 'expecting dictionary for configuration'

    # get and validate config values
    # {

    # only one client supported for now
    if len(config.get('clients', [])) != 1:
        raise Exception("Only one client can be specified")

    # only write mode
    if config.get('mode', 'write') != 'write':
        raise Exception("Only 'write' mode supported for now.")

    # OSDs
    total_osds_in_cluster = teuthology.num_instances_of_type(ctx.cluster, 'osd')
    min_num_osds = config.get('min_num_osds', total_osds_in_cluster)
    max_num_osds = config.get('max_num_osds', total_osds_in_cluster)

    if max_num_osds > total_osds_in_cluster:
        raise Exception('max_num_osds cannot be greater than total in cluster')
    if min_num_osds < 1:
        raise Exception('min_num_osds cannot be less than 1')
    if min_num_osds > max_num_osds:
        raise Exception('min_num_osds cannot be greater than max_num_osd')
    osds = range(0, (total_osds_in_cluster + 1))

    # replicas
    min_num_replicas = config.get('min_num_replicas', 3)
    max_num_replicas = config.get('max_num_replicas', 3)

    if min_num_replicas < 1:
        raise Exception('min_num_replicas cannot be less than 1')
    if min_num_replicas > max_num_replicas:
        raise Exception('min_num_replicas cannot be greater than max_replicas')
    if max_num_replicas > max_num_osds:
        raise Exception('max_num_replicas cannot be greater than max_num_osds')
    replicas = range(min_num_replicas, (max_num_replicas + 1))

    # object size
    sizes = config.get('size', [4 << 20])

    # repetitions
    reps = range(config.get('repetitions', 1))

    # file
    fname = config.get('file', 'radosbench.csv')
    f = open('{}/{}'.format(ctx.archive, fname), 'w')
    f.write(get_csv_header(config) + '\n')
    # }

    # set default pools size=1 to avoid 'unhealthy' issues
    ctx.manager.set_pool_property('data', 'size', 1)
    ctx.manager.set_pool_property('metadata', 'size', 1)
    ctx.manager.set_pool_property('rbd', 'size', 1)

    current_osds_out = 0

    # sweep through all parameters
    for osds_out, size, replica, rep in product(osds, sizes, replicas, reps):

        osds_in = total_osds_in_cluster - osds_out

        if osds_in == 0:
            # we're done
            break

        if current_osds_out != osds_out:
            # take an osd out
            ctx.manager.raw_cluster_cmd(
                'osd', 'reweight', str(osds_out-1), '0.0')
            wait_until_healthy(ctx, config)
            current_osds_out = osds_out

        if osds_in not in range(min_num_osds, (max_num_osds + 1)):
            # no need to execute with a number of osds that wasn't requested
            continue

        if osds_in < replica:
            # cannot execute with more replicas than available osds
            continue

        run_radosbench(ctx, config, f, osds_in, size, replica, rep)

    f.close()

    yield


def get_csv_header(conf):
    all_columns = [
        'rep', 'num_osd', 'num_replica', 'avg_throughput',
        'avg_latency', 'stdev_throughput', 'stdev_latency'
    ]
    given_columns = conf.get('columns', None)
    if given_columns and len(given_columns) != 0:
        for column in given_columns:
            if column not in all_columns:
                raise Exception('Unknown column ' + column)
        return ','.join(conf['columns'])
    else:
        conf['columns'] = all_columns
        return ','.join(all_columns)


def run_radosbench(ctx, config, f, num_osds, size, replica, rep):
    pool = ctx.manager.create_pool_with_unique_name()

    ctx.manager.set_pool_property(pool, 'size', replica)

    wait_until_healthy(ctx, config)

    log.info('Executing with parameters: ')
    log.info('  num_osd =' + str(num_osds))
    log.info('  size =' + str(size))
    log.info('  num_replicas =' + str(replica))
    log.info('  repetition =' + str(rep))

    for role in config.get('clients', ['client.0']):
        assert isinstance(role, six.string_types)
        PREFIX = 'client.'
        assert role.startswith(PREFIX)
        id_ = role[len(PREFIX):]
        (remote,) = ctx.cluster.only(role).remotes.keys()

        proc = remote.run(
            args=[
                'adjust-ulimits',
                'ceph-coverage',
                '{}/archive/coverage'.format(teuthology.get_testdir(ctx)),
                'rados',
                '--no-log-to-stderr',
                '--name', role,
                '-b', str(size),
                '-p', pool,
                'bench', str(config.get('time', 120)), 'write',
            ],
            logger=log.getChild('radosbench.{id}'.format(id=id_)),
            stdin=run.PIPE,
            stdout=BytesIO(),
            wait=False
        )

        # parse output to get summary and format it as CSV
        proc.wait()
        out = proc.stdout.getvalue()
        all_values = {
            'stdev_throughput': re.sub(r'Stddev Bandwidth: ', '', re.search(
                r'Stddev Bandwidth:.*', out).group(0)),
            'stdev_latency': re.sub(r'Stddev Latency: ', '', re.search(
                r'Stddev Latency:.*', out).group(0)),
            'avg_throughput': re.sub(r'Bandwidth \(MB/sec\): ', '', re.search(
                r'Bandwidth \(MB/sec\):.*', out).group(0)),
            'avg_latency': re.sub(r'Average Latency: ', '', re.search(
                r'Average Latency:.*', out).group(0)),
            'rep': str(rep),
            'num_osd': str(num_osds),
            'num_replica': str(replica)
        }
        values_to_write = []
        for column in config['columns']:
            values_to_write.extend([all_values[column]])
        f.write(','.join(values_to_write) + '\n')

    ctx.manager.remove_pool(pool)


def wait_until_healthy(ctx, config):
    first_mon = teuthology.get_first_mon(ctx, config)
    (mon_remote,) = ctx.cluster.only(first_mon).remotes.keys()
    teuthology.wait_until_healthy(ctx, mon_remote)
